How to convert numpy to list

Using the tolist() method in numpy, you can easily convert a numpy array into a Python list. Detailed introduction: 1. Make sure the numpy library has been installed; 2. First import the numpy library and create a numpy array containing integers; 3. Use the tolist() method to convert this numpy array into a Python list and convert it The converted list is output to the console; 4. You will see that the converted list and the numpy array before conversion have the same values, etc.

The operating system for this tutorial: Windows 10 system, Python version 3.11.4, DELL G3 computer.

You can use the tolist() method in the numpy library to convert a numpy array into a Python list. This conversion can be very useful in data processing and analysis. For example, when you need to pass data from a numpy array to other functions or modules, you may need to convert it to a Python list. Below I will explain in detail how to use the tolist() method in numpy for conversion.

First, make sure you have installed the numpy library. If it is not installed, you can use pip to install it:

pip install numpy

Once the installation is complete, you can start using the tolist() method in numpy to perform conversion. Here is a basic example that demonstrates how to convert a numpy array into a Python list:

import numpy as np
# 创建一个numpy数组
arr = np.array([1, 2, 3, 4, 5])
# 使用tolist()方法将numpy数组转换为Python列表
arr_list = arr.tolist()
print(arr_list)

In this example, we first import the numpy library and create a numpy array containing integers. We then use the tolist() method to convert this numpy array to a Python list and output the converted list to the console. You will see that the converted list has the same values ​​as the pre-converted numpy array.

In addition to one-dimensional arrays, the tolist() method can also be applied to multi-dimensional arrays. Here is an example of converting a two-dimensional numpy array to a Python list:

import numpy as np
# 创建一个二维numpy数组
arr = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
# 使用tolist()方法将二维numpy数组转换为Python列表
arr_list = arr.tolist()
print(arr_list)

In this example, we create a numpy array containing two-dimensional data and convert it to Python using the tolist() method list. The converted list will be a nested Python list, with sublists inside corresponding to the rows of the original two-dimensional numpy array.

It should be noted that calling the tolist() method will create a new Python list object and copy the elements in the numpy array to this new list. Therefore, the converted list is a completely separate object from the original numpy array. This means that for very large arrays, the conversion operation may consume a large amount of memory and computing resources.

In addition, the tolist() method is also suitable for conversion of multi-dimensional arrays. Whether it is a one-dimensional, two-dimensional, or higher-dimensional array, it can be converted into the corresponding Python list through the tolist() method.

In short, using the tolist() method in numpy, you can easily convert a numpy array into a Python list. This makes data transfer and manipulation in data processing and analysis more flexible and convenient. I hope these examples will help you and give you a better understanding of how to use numpy's tolist() method to convert data.

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